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Genetic Genealogy (DNA)

How did we end up where we are today? DNA studies have shown that people shared a common ancestor who lived in Africa between 50,000 to 200,000 years ago. As our ancestors migrated out of Africa into the rest of the world, small changes called mutations occurred in their DNA. As generations passed, each mutation links our ancestor to a specific time and place in history. The mutations that we find in our own DNA tell the story of our own ancestral past. Genetic genealogy allows us to trace the path of our ancestors and find out who they were, where they lived and how they have migrated throughout the world.

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.

The two most common types of genetic genealogy tests are Y-DNA (paternal line) and mtDNA (maternal line) genealogical DNA tests. These tests involve the comparison of certain sequences of DNA pairs of individuals in order to estimate the probability that they share a common ancestor in a genealogical time frame and to estimate the number of generations separating the two individuals from their most recent common ancestor.

A man's paternal ancestry can be traced using the DNA on his Y chromosome (Y-DNA) through Y-STR testing. This is useful because the Y chromosome, like many European surnames, passes from father to son, and can be used to help study surnames. Women who wish to determine their paternal ancestry can ask their father, brother, paternal uncle, paternal grandfather, or a cousin who shares the same paternal lineage to take a test for them.

Genetic genealogy has revealed astonishing links between ethnic populations, most commonly referred to as haplogroups. Haplogroups pertain to deep ancestral origins dating back thousands of years. In human genetics, the haplogroups most commonly studied are Y-chromosome (Y-DNA) haplogroups and mitochondrial DNA (mtDNA) haplogroups, both of which can be used to define genetic populations. Mutations can accrue along a certain segment of both molecules and these mutations remain fixed in place on the DNA.

The Rootsweb DNA-Genealogy Internet discussion group has a membership of 750 subscribers from around the world. Some subscribers have had various DNA tests performed and are seeking advice and guidance in interpreting their results. The list also includes administrators of DNA projects that examine surnames, geographic regions, or ethnic groups. The sophistication of subscribers ranges from expert to novice. In some cases, subscribers have been credited with making useful and novel contributions to knowledge in the field of genetic genealogy.

The DNA testing process isn't cheap, but it is helpful to know who exactly your ancestors were.


Trace Your Roots with DNA by Megan Smolenyak Smolenyak and Ann Turner; Rodale Press, 2004.
ISBN: 1-59486-006-8

For more information on using DNA results to discover your family tree, please refer to these web sites:

Animations - in an effort to better explain the complex dynamics of DNA, Sorenson Molecular Genealogy Foundation (SMGF) created the following animations as an introduction to the field of molecular genealogy.

DNA Timeline - a simple history of DNA to use when trying to understand the new field of DNA and genealogy.

Guide for DNA Testing - exactly what to expect from the DNA collection process.

genetic genealogy - further definition of the term on Wikipedia.

genealogical DNA test - one more definition on Wikipedia.

Family Tree DNA - a genetic testing company that specializes in genealogical tests. Our service is dedicated to helping genealogists find lost relatives when the paper trail ends and the brick wall takes its place.

Genetic Genealogy - a website that allows you through DNA research to trace the path of your ancestors and find out who they were, where they lived and how they have migrated throughout the world.

RootsWeb - use the "Search Thingy" search engine to find a DNA discussion group for a particular surname.


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